Wind energy conversion apparatuses of the kind referred to above are already known from German patent publication No. 3331166 A. The horizontal shaft thereby extends in the direction of the oncoming wind, all this in such a manner that the plane of inflow of said wind capturing means extends substantially perpendicularly to the main shaft and also substantially perpendicularly to the direction of the oncoming wind.
For a long time already people have attempted to convert an increasing amount of wind energy into other forms of energy. It is known that this can be achieved by enlarging the area that is covered by the rotating rotor blade. This enlargement can be accomplished by using rotor blades having a greater length. Such longer rotor blades are expensive as regards their construction, however, because they must also be capable of taking up flexural stress induced by the wind and by gyroscopic effects. The length of such a rotor blade is limited by the large mechanical forces to which such long rotor blades are subjected. In addition, such long rotor blades cause the noise level to increase, which renders the use of such wind turbines in built-up areas less desirable.